1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of Related Art
JP-A-2004-037535 or JP-U-56-128618 discloses a liquid crystal display device having a panel heater located on a back side of a liquid crystal display panel. Liquid crystal sealed in the liquid crystal display panel is conditioned by being heated through the panel heater.
JP-U-56-128618 further discloses a temperature detector located adjacent to the liquid crystal display panel. The temperature detector detects ambient temperature of the liquid crystal display panel. When the temperature detector detects the ambient temperature to be low, the panel heater is activated.
However, in a case that the temperature detector is located adjacent to the liquid crystal display panel, the temperature detector is disposed on a substrate of the liquid crystal display panel, for example. Thus, when the heater is activated, heat is transmitted from the heater to the temperature detector through the substrate of the liquid crystal display panel. Because the substrate is typically made of transparent glass or resin having relatively large thermal capacity, it takes certain time to transmit heat from the heater to the temperature detector. Therefore, when liquid crystal is heated by the heater, heat transmission from the heater to the temperature detector is delayed. Thus, detection accuracy may become low, because it is difficult for the temperature detector to immediately detect temperature increasing when the heater is activated.
When the detection accuracy is lowered, liquid crystal may be overheated, because a controllability of the heater is lowered. When liquid crystal is overheated, a contrast of the liquid crystal display panel may be lowered, and a control circuit located adjacent to the overheated liquid crystal may be affected. Thus, a display quality of the liquid crystal display panel may be lowered.